1. Field of the Invention
The present invention relates to a sheet containing apparatus, a sheet feeding apparatus provided with the same, and an image forming apparatus provided with the sheet feeding apparatus and, in particular, to a regulating member for regulating movement of sheets stacked on a sheet stacking means for stacking sheets.
2. Related Background Art
Conventionally, in an image forming apparatus for forming an image on a sheet, such as a printer, facsimile apparatus, copying machine, and a combination of these, there is provided a sheet containing apparatus for containing sheets to be fed to an image forming portion by a sheet feeding apparatus. An example of this sheet containing apparatus is provided with a sheet stacking means for stacking sheets, a side regulating member adapted to move in a direction perpendicular to the sheet feed direction (hereinafter referred to as the “cross direction of a sheet) to regulate the side edges of a sheet, and a trailing edge regulating member adapted to abut against the trailing edges of the stacked sheets on the opposite side to the direction in which the stacked sheets are fed to regulate the position of the sheets in the sheet feed direction, in which the side regulating member and the trailing edge regulating member are moved to their respective predetermined positions in conformity with the sheet size to thereby effect sheet positioning and movement regulation.
Known examples of the positioning method for the regulating members of the conventional sheet containing apparatus include an insertion system in which the regulating members are inserted into insertion holes formed at predetermined positions, and a slide system in which solely the sheet regulating direction of each regulating member is slidably regulated and by inserting a positioning means operated by a lever or the like into an insertion hole formed at a predetermined position at the bottom of each regulating plate, whereby positioning is effected in the sheet regulating direction.
However, in the conventional sheet containing apparatus provided with such regulating members, when, in the case of the insertion system, size change is to be effected, it is necessary to temporarily detach the regulating members from the insertion holes and then reinsert them at predetermined positions, resulting in great consumption of time and effort.
In contrast, in the slide system, it is possible to change the positions of the regulating members solely by sliding the regulating members, so that positioning can be effected easily.
However, in the slide system, the positioning means for the sheet regulating direction is situated below the sheet stacking means, so that the upper portion of an abutment portion of the regulating member abutting against the sheets is subject to deflection so as to open outwardly. Thus, if, when inserting a sheet stack, the abutment portion of the regulating member is pressurized by the sheet stack and its upper portion is outwardly deflected, it is difficult to perform an accurate positioning of the sheet stack above the regulating members, resulting in skew feed or non-feed of the sheet due to the unstableness of the sheet position.